Method of conveying heat energy



J. N. p. HEENAN METHOD OF CONVEYING HEAT ENERGY Filed D96. 11; 1918 Patented Oct. 27, 1925.

UNITED STATES 1,558,871 PATENT OFFICE.

JOHN N. DUNDAS HEENAN, OF OLD COLWYN, ENGLAND, AS SIGNOR T0 POWER SPECIALTY COMPANY, 0'! NEW YORK, Y.

METHOD OF CONVEYING HEAT ENERGY.

Application filed December 11 1918. Serial No. 266,221.

I '0 all whom it may concern: I

Be it known that I, JOHN NELSON DUNDAS HEENAN, a subject of the King of Great Britain, residing at Old Colwyn, North Wales, England, have invented certain new and useful Improvements in Methods of Conveying Heat Energy, of which the fol lowing is a full, clear, and exact description The invention, subject of this application for Letters Patent, may. be most readily comprehended by the following somewhat elementary statement, which While it may appeal more strongly to the layman than to the expert, nevertheless, conveys a correct idea of the nature, the purpose and the scope of the advance in the art which I have made.

Let. it be assumed, by way of illustration, that a given quantity of oil is to be raised to a high temperature: This oil, contained in a suitable tank or receptacle, may not always be practically heated by the direct application of a flame, for obvious reasons, and for this purpose it has been heretofore I customary to heat it by coils within the body of oil through which steam is passed.

This has been found to be a most ideal method of supplying heat at a uniform temperature to a mass of fluid in a tank or. chamber. The temperature in the heating coils may be regulated to a nicety by varying the pressure of the steam, which is maintained at a constant pressure while the condensation takes place .in the coil, and the latent. heat, whichis very large in the case of steam, is delivered to the fluid to be heated. The discharge from such heating coils is water, which is still at the temperature of condensation, and may be returned to the source of steam supply in any suitable manner as by pumping with a comparatively slight expenditure of power. This system is limited for practical purposes to temperatures which correspond to pressures for which boilers and piping are readily obtainable without excessive cost. When higher temperatures are desired, they may be obtained by superheating the steam. superheated steam, however, on entering the heating coils will give up but a small amount of its heat before its temperature drops to a point lower than that required by the coils, and still not sufliciently low to ive-up the large amount of latent heat which it contains. Therefore, the steam must be forced through the coils in. a [gaseous state after having given up a very small amount of heat. In the absence of some appropriate means for utilizing the steam which leaves the coils, it must be blown into the atmosphere with a waste of heat which is prohibitive, as it is not practical to return the uncondensed steam to the boiler. If, however, this steam, which has been lowered somewhat in temperature but not condensed,'is returned to the superheater, none of the rejected heat from the coil will be. wasted, and the steam may be superheated to the original point and passed through a second heating coil and again superheated as many times as may be desired.

As a consequence of increasing the number of passes of the steam between the superheater and the heating coils, the maximum 'drop of the temperature in the heating coils in each pass is reduced directly as the number of passes is increased, thus approach ing closely the ideal conditions of eating .at the temperature due to the pressure and avoids being obliged to carry an impractically high pressure such as over 1000 pounds per square inch which would be necessary for 550 F. temperature. Using my method, the steam pressure would not ordinarily be over 100 pounds per square inch.

Taking a specific case; if the oil bath is to be maintained at a temperature of between 500 and 600 F., the steam would enter the coil in the oil at a temperature of 1000? F. and the temperature reduced by the absorp tion of heat by the oil to approximately 600 and then discharged, the amount of heat given up to the oil by each pound of steam would be approximately 200 B. T. U., while 1000 B. T. U. is wasted in the discharge.

To avoid this loss I propose the following method of procedure; I provide a suitable receptacle for the oil in which I arrange a plurality of heating coils. Through one of these coils I pass the steam froni ta proper boiler after it has passed through a superheater and raised to'a temperature of, say, 1000 F. On its passage through the coil in the oil it gives up to the latter a certain proportion of its heat, and issues from the coil at a temperature, say, of 600 F. I then pass it through another superheater, by which its temperature is raised again to 1000 F., and this reheated steam is passed through another heating coil in the oil and lowered to 600 F. This process is continued until the pressure of the steam, which is reduced by friction in the heating coils and superheater, is practically exhausted.

Taking the case previously cited and as suming the use of six independent heating coils in the oil and six independent superheaters or sections of superheaters, as in each coil the steam will drop from 1000 F. to 600 F. it will give up approximately 200 B. T. U. per pound of steam or a total of 1200 B. '1. U. per pound of steam in the six coils, while the heat lost in the discharge will be the same as before.

This example of heating oil by superheated steam illustrates the applicability of the method to other purposes. By means of the described process, not only steam, bu

any fluid under pressure may be utilized to convey many times the quantity of heat energy it contains when first heated.

, In the accompanying drawings I have at: tempted ,to illustrate the principle, rather than a specific application of the invention, although the fi res may be regarded as showing the met 0d as applied to the heating of a body of oil.

igure 1 is a diagram showing the means of carrying out the method, and

Fig. 2 is a modification of the same.

In Fig. 1, 2 designates a container or tank for oil, having inlet and outlet pipes and cocks 3, 4, and containing a plurality of heating coils 5, 6, 7, the number of which is not material.

The means for heating and reheating the steam is conventionally shown as a chamber 8 containing superheater coils 9, 10 and 11, with oil flames 12 under each for heating the same. I

In the operation of this device the steam enters the superheater 9 where its temperature is raised to the desired extent, and then passed through the heating coil 5. From thence the cooled steam at somewhat reduced pressure is passed to and through the superheater 10, where its temperature is again raised, and from thence it is passed through the second coil 6, and so on; the number of superheaters and coils being, if so desired, sufiicient to drop the pressure to zero.

In Fig. 2 a similar means is shown, but in this case a separatel fired superheater 13 is shown, and the pre 'erred and more advantageous arrangement is indicated by which the heating medium and that to be heated are caused to flow in opposite directions. The steam, for example, enters the superheater 9, which, being farthest from the fire 14, has the greatest number of coils. From this it passes through the heating coil 5, which is in the hottest part of the oil and has the smallest number of coils. In the same way the number of superheater coils is reduced as their position approaches the point of greatest heat, and the number of heating coils increases in'proportion to the amount of heat that is to be absorbed from them.

Certain obvious advantages follow from the use of this apparatus and method. For example, by condensing the steam after it leaves the last healilll coil, a part of the latent heat may be recovered in the feed water for the boiler, or a partial vacuum may be obtained which would make it possible to add more sections and thus to secure greater economy. Furthermore, the

system also increases the eificiency very greatly by increasing the diflerential temperature between the medium to be heated,

and the heating medium.

As above intimated, the method may be carried out by the use of any fluid medium under pressure and with suitable provisions forheating it. The invention is not limited to the specific purpose of heating oil but is applicable in all cases where a fluid under pressure is utilized to convey heat energy to other media whose properties or uses require it. What I therefore claim as my invention 1s:

A fluid heater comprising a receptacle for the fluid to be heated, a plurality of heating coils in said receptacle adapted to heat JOHN NELSON DUNDAS HEENAN.

Certificate of Correction.

It is hereby certified that in Letters PatentNo. 1,558,871, granted October 27,

1925 uponthe application of-JohnjNelsDn Dundas Heenan, of Old Colwyn, England, for an improvement in Methods of Conveying Heat Energy, errors appear in the printed-specification requiring correction as follows: In the drawing the numeral 20 should be applied to the pump in Fig. 2; page 2, after line 71, insert the paragraph A mp 20 or other suitable device may be employed to supply the steam or-other keatmg medium under pressure to the inlet end of the rolls 9.; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record'of the case in the Patent Oflice.

Signed and sealed this 19th day of January, A. D. 1926.

[SEAL] WM. A. KIN'NAN,

Acting Gammissz'oner of Patents. 

